I think that the community should emphasize that it is a community of wannabe-rationalists whose goal is to self-improve, overcome bias and learn the secrets of the Bayes or whatever. Just as this blog does. I think that that would weed out the likes of the Rational Response Squad, which is an example of what we don’t want a rationalist community to be like!
At the same time I don’t think that a rationalist community should be any more elitist than necessary. It should fulfill part of the same purpose as your planned popular book.